The Bluetooth technology is an open standard of the wireless data and voice transmission, which mainly solves the wireless communication problem within short distance, and the effective communication distance is generally within 10 meters. The Bluetooth protocol standard is formulated and released by the SIG organization.
According to the different applications of the Bluetooth, the standard defines different application framework profiles. Wherein, in order to watch video on the Bluetooth media output device, it defines the video distribution profile (VDP); in order to realize the control function conveniently through the Bluetooth control device as well when listening to the stereosound music or watching the video media on the Bluetooth media output device, it stipulates the audiovideo remote control profile (AVRCP).
In a section of AVRCP 1.4, “4.5 Categories”, it defines the common media playing control command, for example: play, stop, pause, forward, backward, etc. The video file will often carry with the subtitle while playing, and may provide a plurality of subtitle files in different languages, and these subtitle files can be loaded through the media player and displayed on the output interface of the media player synchronously with the audiovideo, but the AVRCP does not stipulate the operation command word (operation_id) corresponding to switching different subtitles, so that the strong extension control function which the multimedia player itself possesses is unable to be completed through the Bluetooth control device.